Area Forecast Discussion
Issued by NWS North Platte, NE

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FXUS63 KLBF 312232
AFDLBF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
532 PM CDT FRI OCT 31 2014

.SYNOPSIS...
ISSUED AT 529 PM CDT FRI OCT 31 2014

A HIGH AMPLITUDE UPPER AIR PATTERN CONTINUES ACROSS THE CONUS AND
CANADA TODAY. A LARGE TROUGH OF LOW PRESSURE EXTENDED SOUTH FROM
NRN QUEBEC INTO FLORIDA. FURTHER WEST...A RIDGE EXTENDED FROM THE
FOUR CORNERS NORTH TO NORTHERN PORTIONS OF THE NORTHWEST
TERRITORIES OF CANADA. A SECOND TROUGH OF LOW PRESSURE WAS LOCATED
ALONG THE WEST COAST FROM ALASKA SOUTH TO COASTAL CALIFORNIA. HT
RISES OF 50 TO 100 METERS WERE NOTED ACROSS THE DAKOTAS...NEBRASKA
AND NORTHERN MN THIS MORNING...WITH 50 TO 100 METER HT FALLS
EXTENDING FROM NRN CALIFORNIA AND NEVADA...NWD TO THE YUKON. AT
THE SURFACE...A MASSIVE AREA OF HIGH PRESSURE EXTENDED FROM
WESTERN ONTARIO INTO EASTERN NEBRASKA. A STRONG PRESSURE GRADIENT
HAS DEVELOPED ACROSS THE HIGH PLAINS THIS AFTERNOON WITH DECENT
SOUTHERLY WINDS EXTENDING FROM EASTERN COLORADO INTO THE CENTRAL
AND WESTERN DAKOTAS. ACROSS WESTERN AND NORTH CENTRAL
NEBRASKA...WINDS WERE FROM THE SOUTH AT 10 TO 20 MPH WITH MOSTLY
CLEAR SKIES. TEMPERATURES WERE COOL THIS AFTERNOON WITH 2 PM CDT
READINGS RANGING FROM 39 AT ONEILL...TO 45 AT OGALLALA.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 529 PM CDT FRI OCT 31 2014

UPPER LEVEL RIDGING ALOFT WILL BUILD EAST INTO THE CENTRAL PORTIONS
OF THE UNITED STATES TONIGHT INTO SATURDAY. UNDERNEATH THE RIDGE...A
DEVELOPING LEEWARD TROUGH WILL HELP TIGHTEN THE SURFACE PRESSURE
GRADIENT FROM EAST TO WEST. PRESSURE VALUES BY SATURDAY AFTERNOON
WILL RANGE FROM AROUND 1024MB IN EASTERN NEBRASKA...TO 1005MB ACROSS
THE PANHANDLE. THIS WILL SET THE STAGE FOR GUSTY SOUTH
WINDS...ESPECIALLY DURING THE DAY SATURDAY. WINDS WILL INCREASE SOME
TONIGHT THOUGH AS THE SOUTHERLY LOW LEVEL JET INCREASES TO BETWEEN
50 AND 60 KTS LATE THIS EVENING. THIS SHOULD HELP KEEP LOW
TEMPERATURES FROM FALLING MUCH BELOW 30 DEGREES AT MOST LOCATIONS.
IF IT WOULD HAPPEN TO DECOUPLE MORE THAN FORECASTED IN LOWER LYING
AREAS...THEN UPPER 20S WOULD PROBABLY BE REALIZED IN THOSE AREAS.

AS MENTIONED A TIGHT PRESSURE GRADIENT WILL RESIDE ACROSS THE REGION
SATURDAY...WITH GUSTY SOUTH WINDS EXPECTED. NAM MODEL 500M WIND
SPEEDS OF 25 KTS EAST OF HIGHWAY 83...SUGGEST THAT SUSTAINED WIND
SPEEDS OF 25 MPH ARE POSSIBLE. DESPITE THE SOUTH WINDS...CHILLY
TEMPERATURES ARE STILL EXPECTED SATURDAY...AS SOME COLD AIR IS
RECYCLED BACK NORTH INTO THE AREA FROM THE SOUTHERN PLAINS. HIGHS
SHOULD REACH AROUND 50 FROM BROKEN BOW...NORTHEAST THROUGH ONEILL.
FARTHER WEST...LOWER 60S ARE EXPECTED ACROSS FAR SOUTHWEST NEBRASKA
INTO THE PANHANDLE.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 529 PM CDT FRI OCT 31 2014

SATURDAY NIGHT THROUGH MONDAY...THE UPPER LEVEL RIDGE CONTINUES
EASTWARD ACROSS THE FORECAST AREA...WITH THE RIDGE AXIS BY THE
NEBRASKA/IOWA BORDER BY 02/12Z. AHEAD OF THE APPROACHING
TROUGH...SOUTHERLY SURFACE WINDS NEVER DISSIPATE OVERNIGHT
SATURDAY INTO SUNDAY AND 850HPA WINDS STAY AOA 15 KTS THROUGH
02/12Z...LIMITING DECOUPLING. BUMPED MIN TEMPS UP A DEGREE OR TWO
EXCEPT IN THE PLATTE RIVER VALLEY WHERE WINDS COULD BE A LITTLE
LIGHTER...ESPECIALLY TOWARD DAYBREAK.

SUNDAY...BLENDED MAX TEMPS TOWARD THE BC EURO AND BC MET TO ACCOUNT
FOR BETTER HANDLING OF THE DOWNSLOPING WINDS AND WARM AIR ADVECTION.
THIS COMBINATION WILL LIKELY KEEP HIGHS IN THE LOW 70S ACROSS THE
SANDHILLS AND SOUTHWEST NEBRASKA. COMPRESSIONAL HEATING AHEAD OF THE
SURFACE TROUGH AND EARLY SUNSHINE WILL ALSO HELP TEMPERATURES RISE
15 TO 20 DEGREES ABOVE NORMAL. ONE CAVEAT IN THE HIGHS MAY BE
INCREASED CLOUDINESS TOWARD PEAK HEATING OF THE DAY IF CIRRUS
DEVELOPMENT OFF THE ROCKIES MOVES INTO WESTERN NEBRASKA. MOVED POPS
WEST OF A LINE FROM OGA TO VTN IN THE 03/00 TO 03/06Z TIME
FRAME...WHERE THE MID LEVEL HUMIDITY IS HIGHER AND BETTER
FRONTOGENESIS IS PRESENT. OVERNIGHT SUNDAY INTO MONDAY...AN 850HPA
WARM FRONT MOVES NORTH ACROSS THE SANDHILLS ON THE NOSE OF THE
LOW LEVEL JET. A NARROW RIBBON OF ELEVATED CAPE TO 500 J/KG ALONG
WITH LIFTED INDICES TO -2 AND SPEED CONVERGENCE ARE INDICATED BY
THE NAM...WHICH IF COMES TRUE...MAY RESULT IN A RUMBLE OF THUNDER
OR TWO.

MONDAY...THE GFS AND NAM SHOW THE SURFACE COLD FRONT PASSAGE THROUGH
WESTERN NEBRASKA DURING THE MORNING HOURS. DUE TO POST FRONTAL
MOISTURE AND THE LAGGING UPPER LEVEL FRONT...KEPT MENTION OF POPS
THROUGH AT LEAST 04/00Z ACROSS THE FORECAST AREA. CLOUD COVER AND
COLD AIR ADVECTION WILL LIMIT MAX TEMPS TO THE UPPER 40S TO MID 50S.

MONDAY NIGHT THROUGH FRIDAY...THE SHORTWAVE MOVES EAST OF THE
FORECAST AREA MONDAY NIGHT WITH NORTHWEST FLOW AT 500HPA SOON TO
FOLLOW. BY THURSDAY...THE EURO TRANSITIONS UPPER LEVEL FLOW TO
ZONAL ACROSS NEBRASKA AND CONTINUES IT INTO FRIDAY. THE GFS KEEPS
NORTHWEST FLOW ACROSS THE STATE INTO THE WEEKEND. IN EITHER
CASE...NO PRECIPITATION IS EXPECTED AS THERE IS NO REAL MOISTURE
SOURCE AT THE SURFACE OF ALOFT. 500HPA HEIGHTS REMAIN AROUND 5760M
AND 850HPA TEMPS GENERALLY BETWEEN 5 AND 10C. TEMPERATURES IN THE
EXTENDED FORECAST ARE FORECAST TO REMAIN AT OR ABOVE CLIMO.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 529 PM CDT FRI OCT 31 2014

BREEZY CONDITIONS WILL DEVELOP TONIGHT AND ESPECIALLY SATURDAY
ACROSS WESTERN AND NORTH CENTRAL NEBRASKA...AS A TIGHT SURFACE
PRESSURE GRADIENT DEVELOPS. WINDS COULD GUST OVER 30
KTS...ESPECIALLY FROM VTN...EAST THROUGH ANW AND ONL. OTHERWISE NO
METEOROLOGICAL HAZARDS TO AVIATION ARE EXPECTED.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SYNOPSIS...WFO LBF
SHORT TERM...WFO LBF
LONG TERM...WFO LBF
AVIATION...WFO LBF




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